I've read that article more times than I can count.  It still doesn't explain the equation(s) used to go from the private key to the public key.  It just says "1) Have a private ECDSA key. 2) Take the public key generated with it (65 bytes, 1 byte 0x04, 32 bytes corresponding to X coordinate, 32 bytes corresponding to Y coordinate)."  I do not understand how that public key is generated, despite reading several articles on elliptic curve cryptography.